Defining Antecedent Topography at Coral Pink Sand Dunes, Kane County, Utah: The Influence of Structural Controls on Dune-Field Boundary Conditions and Holocene Landscape Evolution

摘要

Dune fields are transient features that record climate signatures through changes in mobility, morphology, and patterning. Aeolian geomorphologists are increasingly recognizing the important role that pre-existing, antecedent topography plays in controlling boundary conditions that affect changes in dune patterning. However, the dynamic relationship between antecedent topography and climate-sensitive boundary conditions is relatively unexplored. Here, I define antecedent topography for the Coral Pink Sand Dunes in southern Utah and show that structural controls play an important role in shaping antecedent geomorphic conditions of this dune field. I use ground-based terrestrial laser scanning (TLS) to produce a high-resolution digital elevation model (DEM), which is used to extract the trend of underlying topography. This detrended model is used to identify areas within the dune field where there is a high potential for structural control of the underlying topography. I validate and further resolve this antecedent-topography model using ground-penetrating radar (GPR) to image the subsurface. Results show that CPSD has a complex and heterogeneous underlying topography, with variable structural influence, that affects dune morphology and patterning by creating variability in sediment supply, moisture gradients, and wind direction, and by confining the lateral extent of the dune field.